Traditionally cottage cheese has been made in open vats. After coagulation of the cheese curds, the curds are cut by a wire frame moved longitudinally along the length of the vat either manually or by a mechanically traversing mechanism. The curds are then cross cut manually by dragging wire harps through the curds. As cottage cheese curds contain very little fat, the curds are fragile and are easily fragmented. With the use of the conventional wire frames and harps, the curds tend to be damaged as they are extruded between the wires.
After cutting the cheese curds are cooked by heating with gentle agitation. The heat is usually supplied through a heated jacket, or by the direct introduction of steam into the vat.
More recently, closed cheese making vats, such as that shown in U.S. Pat. No. Re. 29,967, have replaced open top vats. The closed cheese making vat of the aforementioned patent, can be sealed to the atmosphere during the entire cheese making operation to minimize contamination of the product. With the use of the closed vat, the same implements, which are permanently mounted on the rotating frame, are utilized for both the cutting and stirring operations and it is not necessary to remove and replace the implements during the cheese making operation. This feature reduces the overall cost of the unit, as well as decreasing the labor necessary for installation and removal of various implements.
The cutting and stirring implements, as described in the U.S. Pat. No. Re. 29,967, comprise a series of vertical blades which are mounted on the rotating frame. The blades are designed so that when the shaft is rotated in one direction, a minimum frontal area is provided so that the blades act to cut or slide the curds. When the shaft is rotated in the opposite direction, the blades provide a maximum frontal area to stir or agitate the product.